Copolycarbonate and composition containing the same

ABSTRACT

Disclosed is a polycarbonate composition including a polycarbonate; and a copolycarbonate, where the copolycarbonate includes: an aromatic polycarbonate-based first repeating unit; and aromatic polycatbonate-based second repeating units having siloxane bonds, which include a repeating unit represented by Chemical Formula 2 and a repeating unit represented by Chemical Formula 3, where the ratio of an impact strength at room temperature and an impact strength at low-temperature (impact strength at room temperature/impact strength at low-temperature) as measured at 23° C. and −30° C., respectively, in accordance with ASTM D256 (⅛ inch, Notched Izod) is 1.01 to 1.30, and the impact strength at room temperature is 840 to 1000 J/m:

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application is a National Stage Entry of International ApplicationNo. PCT/KR2015/012292, filed Nov. 16, 2015, and claims the benefit ofand priority to Korean Application Nos. 10-2014-0173005, filed on Dec.4, 2014, 10-2015-0106021, filed on Jul. 27, 2015, and 10-2015-0159657,filed on Nov. 13, 2015, all of which are hereby incorporated byreference in their entirety for all purposes as if fully set forthherein.

TECHNICAL FIELD

The present invention relates to a copolycarbonate and a compositioncomprising the same, and more specifically to a copolycarbonate beingeconomically produced, and having small difference between an impactstrength at room temperature and an impact strength at low-temperature,and to a composition comprising the same.

BACKGROUND OF ART

Polycarbonate resins are prepared by condensation-polymerization of anaromatic diol such as bisphenol A with a carbonate precursor such as aphosgene and have excellent impact strength, dimensional stability, heatresistance and transparency. Thus, the polycarbonate resins haveapplication in a wide range of uses, such as exterior materials ofelectrical and electronic products, automobile parts, buildingmaterials, and optical components.

Recently, in order to apply these polycarbonate resins to more variousfields, many studies have been made to obtain desired physicalproperties by copolymerizing two or more aromatic diol compounds havingdifferent structures from each other and introducing units havingdifferent structures in a main chain of the polycarbonate.

Especially, studies for introducing a polysiloxane structure in a mainchain of the polycarbonate have been undergone, but most of thesetechnologies have disadvantages in that production costs are high, andwhen chemical resistance or impact strength, particularly impactstrength at low-temperature is increased, a melt index or the like islowered.

Given the above circumstances, the present inventors have conductedintensive studies to overcome the above-mentioned disadvantagesencountered with the prior arts and develop a copolycarbonate havingsmall difference between an impact strength at room temperature and animpact strength at low-temperature, and thus exhibiting an excellentimpact resistance, and found that a copolycarbonate in which a specificsiloxane compound is introduced in a main chain of the polycarbonate asdescribed below satisfies the above-described properties. The presentinvention has been completed on the basis of such a finding.

DETAILED DESCRIPTION OF THE INVENTION Technical Problem

It is an object of the present invention to provide a copolycarbonatehaving small difference between an impact strength at room temperatureand an impact strength at low-temperature, thereby exhibiting anexcellent impact resistance.

It is a further object of the present invention to provide a compositioncomprising the above-mentioned copolycarbonate.

Technical Solution

In order to achieve these objects, the present invention provides acopolycarbonate comprising: an aromatic polycarbonate-based firstrepeating unit; and one or more aromatic polycarbonate-based secondrepeating units having siloxane bonds, wherein the ratio of an impactstrength at room temperature and an impact strength at low-temperature(impact strength at room temperature/impact strength at low-temperature)as measured at 23° C. and −30° C., respectively, in accordance with ASTMD256 (⅛ inch, Notched Izod) is 1.01 to 1.30, and the impact strength atroom temperature is 840 to 1000 J/m.

As described above, the copolycarbonate according to the presentinvention has characterisitics in that it has small difference betweenan impact strength at room temperature and an impact strength atlow-temperature and thus exhibits an excellent impact resistance.Preferably, the ratio of an impact strength at room temperature and animpact strength at low-temperature (impact strength at roomtemperature/impact strength at low-temperature) is not more than 1.29,not more than 1.28, not more than 1.27 not more than 1.26, not more than1.25, not more than 1.24, not more than 1.23, not more than 1.22, notmore than 1.21, not more than 1.20, not more than 1.19, not more than1.18, not more than 1.17, not more than 1.16, not more than 1.15, notmore than 1.14, not more than 1.13, not more than 1.12, not more than1.11, not more than 1.10, not more than 1.09, or not more than 1.08; andnot less than 1.02, not less than 1.03, or not less than 1.04.

Preferably, the impact strength at low-temperature is not less than 650J/m, not less than 700 J/m, not less than 750 J/m, not less than 800J/m, not less than 850 J/m, or not less than 900 J/m. In addition, theimpact strength at low-temperature is excellent when the value is high,and thus it is not limited to any upper limit value. As one example,however, it may be not more than 990 J/m, not more than 980 J/m, notmore than 970 J/m, not more than 960 J/m or not more than 950 J/m.

Further, preferably, the impact strength at room temperature is not lessthan 850 J/m, not less than 860 J/m, not less than 870 J/m, not lessthan 880 J/m, not less than 890 J/m, not less than 900 J/m, not lessthan 910 J/m, not less than 920 J/m, not less than 930 J/m, not lessthan 940 J/m, not less than 950 J/m, or not less than 960 J/m. Further,the impact strength at room temperature is excellent when the value ishigher, and thus it is not limited to any upper limit value. As oneexample, however, it may be not more than 1000 J/m, not more than 990J/m, not more than 980 J/m, or not more than 970 J/m.

Further, preferably, the copolycarbonate has a melt index of 3 to 20g/10 min as measured in accordance with ASTM D1238 (300° C., 1.2 kgconditions).

Further, preferably, the copolycarbonate has YI (yellow index) of 2 to6.5 as measured in accordance with ASTM 01925. Preferably, YI (yellowindex) is not less than 2; and not more than 6.0, not more than 5.5, notmore than 5.0, not more than 4.5, not more than 4.0, not more than 3.5,not more than 3.0, or not more than 2.5.

Further, the copolycarbonate according to the present invention has aweight average molecular weight of 1,000 to 100,000 g/mol and preferably15,000 to 35,000 g/mol. More preferably, the above weight averagemolecular weight is not less than 20,000 g/mol, not less than 21,000g/mol, not less than 22,000 g/mol, not less than 23,000 g/mol, not lessthan 24,000 g/mol, not less than 25,000 g/mol, not less than 26,000g/mol, not less than 27,000 g/mol, or not less than 28,000 g/mol.Further, the above weight average molecular weight is not more than34,000 g/mol, not more than 33,000 g/mol, or not more than 32,000 g/mol.

Further, preferably, the copolycarbonate comprises two kinds of aromaticpolycarbonate-based second repeating units having the siloxane bonds.

Further, the mole ratio of the aromatic polycarbonate-based firstrepeating unit and one or more aromatic polycarbonate-based secondrepeating units having siloxane bonds is preferably 1:0.004-0.006, andthe weight ratio thereof is preferably 1:0.04-0.07.

In particular, the aromatic polycarbonate-based first repeating unit isformed by reacting an aromatic diol compound and a carbonate precursor,and it is preferably represented by the following Chemical Formula 1:

in the above Chemical Formula 1,

R₁, R₂, R₃ and R₄ are each independently hydrogen, C₁₋₁₀ alkyl, C₁₋₁₀alkoxy, or halogen,

Z is C₁₋₁₀ alkylene unsubstituted or substituted with phenyl, C₃₋₁₅cycloalkylene unsubstituted or substituted with C₁₋₁₀ alkyl, O, S, SO,SO₂, or CO.

Preferably, R₁, R₂, R₃ and R₄ are each independently hydrogen, methyl,chloro, or bromo.

Further, Z is preferably a linear or branched C₁₋₁₀ alkyleneunsubstituted or substituted with phenyl, and more preferably methylene,ethane-1,1-diyl, propane-2,2-diyl, butane-2,2-diyl,1-phenylethane-1,1-diyl or diphenylmethylene. Further, preferably, Z iscyclohexane-1,1-diyl, O, S, SO, SO₂, or CO.

Preferably, the repeating unit represented by Chemical Formula 1 may bederived from one or more aromatic diol compounds selected from the groupconsisting of bis(4-hydroxyphenyl)methane, bis(4-hydroxyphenyl)ether,bis(4-hydroxyphenyl)sulfone, bis(4-hydroxyphenyl)sulfoxide,bis(4-hydroxyphenyl)sulfide, bis(4-hydroxyphenyl)ketone,1,1-bis(4-hydroxyphenyl)ethane, bisphenol A,2,2-bis(4-hydroxyphenyl)butane, 1,1-bis(4-hydroxyphenyl)cyclohexane,2,2-bis(4-hydroxy-3,5-dibromophenyl)propane,2,2-bis(4-hydroxy-3,5-dichlorophenyl)propane,2,2-bis(4-hydroxy-3-bromophenyl)propane,2,2-bis(4-hydroxy-3-chlorophenyl) propane,2,2-bis(4-hydroxy-3-methylphenyl)propane,2,2-bis(4-hydroxy-3,5-dimethylphenyl)propane,1,1-bis(4-hydroxyphenyl)-1-phenyl ethane,bis(4-hydroxyphenyl)diphenylmethane, andα,ω-bis[3-(o-hydroxyphenyl)propyl]polydimethylsiloxane.

As used herein, ‘derived from aromatic diol compounds’ means that ahydroxy group of the aromatic dial compound and a carbonate precursorare reacted to form the repeating unit represented by Chemical Formula1.

For example, when bisphenol A which is an aromatic diol compound, andtriphosgene which is a carbonate precursor, are polymerized, therepeating unit represented by Chemical Formula 1 is represented by thefollowing Chemical Formula 1-1:

The carbonate precursor used herein may include one or more selectedfrom the group consisting of dimethyl carbonate, diethyl carbonate,dibutyl carbonate, dicyclohexyl carbonate, diphenyl carbonate, ditolylcarbonate, bis(chlorophenyl)carbonate, di-m-cresyl carbonate, dinaphthylcarbonate, bis(diphenyl)carbonate, phosgene, triphosgene, diphosgene,bromo phosgene and bishalo formate. Preferably, triphosgene or phosgenemay be used.

The one or more aromatic polycarbonate-based second repeating unitssiloxane bonds are formed by reacting one or more siloxane compounds anda carbonate precursor, and it comprises preferably a repeating unitrepresented by the following Chemical Formula 2 and a repeating unitrepresented by the following Chemical Formula 3:

in the above Chemical Formula 2,

each of X₁ is independently C₁₋₁₀ alkylene,

each of R₅ is independently hydrogen; C₁₋₁₅ alkyl unsubstituted orsubstituted with oxiranyl, oxiranyl-substituted C₁₋₁₀ alkoxy, or C₆₋₂₀aryl; halogen; C₁₋₁₀ alkoxy; allyl; C₁₋₁₀ haloalkyl; or C₆₋₂₀ aryl, and

n is an integer of 10 to 200,

in the above Chemical Formula 3,

each of X₂ is independently C₁₋₁₀ alkylene,

each of Y₁ is independently hydrogen, C₁₋₆ alkyl, halogen, hydroxy, C₁₋₆alkoxy or C₆₋₂₀ aryl,

each of R₆ is independently hydrogen; or C₁₋₁₅ alkyl unsubstituted orsubstituted with oxiranyl, oxiranyl-substituted C₁₋₁₀ alkoxy, or C₆₋₂₀aryl; halogen; C₁₋₁₀ alkoxy; allyl; C₁₋₁₀ haloalkyl; or C₆₋₂₀ aryl, and

m is an integer of 10 to 200.

In Chemical Formula 2, each of X₁ is independently preferably C₂₋₁₀alkylene, more preferably C₂₋₄ alkylene and most preferablypropane-1,3-diyl.

Also, preferably, each of R₅ is independently hydrogen, methyl, ethyl,propyl, 3-phenylpropyl, 2-phenylpropyl, 3-(oxiranylmethoxy)propyl,fluoro, chloro, bromo, iodo, methoxy, ethoxy, propoxy, allyl,2,2,2-trifluoroethyl, 3,3,3-trifluoropropyl, phenyl, or naphthyl. Inaddition, each of R₅ is independently preferably C₁₋₁₀ alkyl, morepreferably C₁₋₆ alkyl, still more preferably C₁₋₃ alkyl and mostpreferably methyl.

Further, preferably, n is an integer of not less than 10, not less than15, not less than 20, not less than 25, not less than 30, not less than31, or not less than 32; and not more than 50, not more than 45, notmore than 40, not more than 39, not more than 38, or not more than 37.

In Chemical Formula 3, each of X₂ is independently preferably C₂₋₁₀alkylene, more preferably C₂₋₆ alkylene and most preferably isobutylene.

Further, preferably, Y₁ is hydrogen.

Further, preferably, each of R₆ is independently hydrogen, methyl,ethyl, propyl, 3-phenylpropyl, 2-phenylpropyl,3-(oxiranylmethoxy)propyl, fluoro, chloro, bromo, iodo, methoxy, ethoxy,propoxy, allyl, 2,2,2-trifluoroethyl, 3,3,3-trifluoropropyl, phenyl, ornaphthyl. Further, preferably, each of R₆ is independently C₁₋₁₀ alkyl,more preferably C₁₋₆ alkyl, still more preferably C₁₋₃ alkyl, and mostpreferably methyl.

Preferably, m is not less than 40, not less than 45, not less than 50,not less than 55, not less than 56, not less than 57, or not less than58; and not more than 80, not more than 75, not more than 70, not morethan 65, not more than 64, not more than 63, or not more than 62.

The repeating unit represented by Chemical Formula 2 and the repeatingunit represented by Chemical Formula 3 are, respectively, derived from asiloxane compound represented by the following Chemical Formula 2-1 anda siloxane compound represented by the following Chemical Formula 3-1:

in the above Chemical Formula 2-1, X₁, R₅ and n are the same aspreviously defined.

in the above Chemical Formula 3-1, X₂, Y₁, R₆ and m are the same aspreviously defined.

As used herein, ‘derived from a siloxane compound’ means that a hydroxygroup of the respective siloxane compound and a carbonate precursor arereacted to form the repeating unit represented by Chemical Formula 2 andthe repeating unit represented by Chemical Formula 3. Further, thecarbonate precursors that can be used for the formation of the repeatingunits represented by Chemical Formulae 2 and 3 are the same as thosedescribed for the carbonate precursor that can be used for the formationof the repeating unit represented by Chemical Formula 1 described above.

The methods for preparing the siloxane compound represented by ChemicalFormula 2-1 and the siloxane compound represented by Chemical Formula3-1 are represented by the following Reaction Schemes 1 and 2:

in the above Reaction Scheme 1,

X₁′ is C₂₋₁₀ alkenyl, and

X₁, R₅ and n are the same as previously defined.

in the above Reaction Scheme 2,

X₂′ is C₂₋₁₀ alkenyl, and

X₂, Y₁, R₆ and m are the same as previously defined.

In Reaction Scheme 1 and Reaction Scheme 2, the reaction is preferablyconducted in the presence of a metal catalyst. As the metal catalyst, aPt catalyst is preferably used. The Pt catalyst used herein may includeone or more selected from the group consisting of Ashby catalyst,Karstedt catalyst, Lamoreaux catalyst, Speier catalyst, PtCl₂(COD),PtCl₂(benzonitrile)₂ and H₂PtBr₆. The metal catalyst may be used in anamount of not less than 0.001 parts by weight, not less than 0.005 partsby weight, or not less than 0.01 parts by weight; and not more than 1part by weight, not more than 0.1 part by weight, or not more than 0.05part by weight, based on 100 parts by weight of the compoundsrepresented by the Chemical Formulae 7 or 9.

Further, the above reaction temperature is preferably 80 to 100° C.Further, the above reaction time is preferably 1 to 5 hours.

In addition, the compounds represented by Chemical Formulae 7 or 9 canbe prepared by reacting an organodisiloxane and an organocyclosiloxanein the presence of an acid catalyst, and n and m may be adjusted byadjusting the amount of the reactants used.

The reaction temperature is preferably 50 to 70° C. Also, the reactiontime is preferably 1 to 6 hours.

The above organodisiloxane may include one or more selected from thegroup consisting of tetramethyldisiloxane, tetraphenyldisiloxane,hexamethyldisiloxane and hexaphenyldisiloxane. In addition, the aboveorganocyclosiloxane may include, for example, organocyclotetrasiloxane.As one example thereof, octamethylcyclotetrasiloxane andoctaphenylcyclotetrasiloxane and the like can be included.

The above organodisiloxane can be used in an amount of not less than 0.1parts by weight, or not less than 2 parts by weight; and not more than10 parts by weight, or not more than 8 parts by weight, based on 100parts by weight of the organocyclosiloxane.

The above acid catalyst that may be used herein includes one or moreselected from the group consisting of H₂SO₄, HClO₄, AlCl₃, SbCl₅, SnCl₄and acid clay (fuller's earth). Further, the acid catalyst may be usedin an amount of not less than 0.1 parts by weight, not less than 0.5parts by weight, or not less than 1 part by weight; and not more than 10parts by weight, not more than 5 parts by weight, or not more than 3parts by weight, based on 100 parts by weight of theorganocyclosiloxane.

In particular, by adjusting the content of the repeating unitrepresented by Chemical Formula 2 and the repeating unit represented byChemical Formula 3, the impact resistance at low-temperature and themelt index of the copolycarbonate can be improved simultaneously.Preferably, the weight ratio between the repeating units may be from1:99 to 99:1. Preferably, the weight ratio is from 3:97 to 97:3, from5:95 to 95:5, from 10:90 to 90:10, or from 15:85 to 85:15, and morepreferably from 20:80 to 80:20. The weight ratio of the above repeatingunits corresponds to the weight ratio of siloxane compounds, for examplethe siloxane compound represented by Chemical Formula 2-1 and thesiloxane compound represented by Chemical Formula 3-1.

Preferably, the repeating unit represented by Chemical Formula 2 isrepresented by the following Chemical Formula 2-2:

in the above Chemical Formula 2-2, R₅ and n are the same as previouslydefined. Preferably, R₅ is methyl.

Also, preferably, the repeating unit represented by Chemical Formula 3is represented by the following Chemical Formula 3-2:

in the above Chemical Formula 3-2, R₆ and m are the same as previouslydefined. Preferably, R₆ is methyl.

Further, preferably, the copolycarbonate according to the presentinvention comprises all of the repeating unit represented by ChemicalFormula 1-1, the repeating unit represented by Chemical Formula 2-2, andthe repeating unit represented by Chemical Formula 3-2.

Further, the present invention provides a method for preparing acopolycarbonate comprising a step of polymerizing the aromatic diolcompound, the carbonate precursor and one or more siloxane compounds.

The aromatic diol compound, the carbonate precursor and the one or moresiloxane compounds are the same as previously described.

During the polymerization, the one or more siloxane compounds can beused in an amount of not less than 0.1% by weight, not less than 0.5% byweight, not less than 1% by weight, or not less than 1.5% by weight; andnot more than 20% by weight, not more than 10% by weight, not more than7% by weight, not more than 5% by weight, not more than 4% by weight,not more than 3% by weight, or not more than 2% by weight, based on 100%by weight in total of the aromatic dial compound, the carbonateprecursor and the one or more siloxane compounds. Also, the abovearomatic dial compound can be used in an amount of not less than 40% byweight, not less than 50% by weight, or not less than 55% by weight; andnot more than 80% by weight, not more than 70% by weight, or not morethan 65% by weight, based on 100% by weight in total of the aromaticdial compound, the carbonate precursor and the one or more siloxanecompounds. The above carbonate precursor can be used in an amount of notless than 10% by weight, not less than 20% by weight, or not less than30% by weight; and not more than 60% by weight, not more than 50% byweight, or not more than 40 by weight, based on 100% by weight in totalof the aromatic diol compound, the carbonate precursor and the one ormore siloxane compounds.

Further, as the polymerization method, an interfacial polymerizationmethod can be used as one example. In this case, there is an effect inthat the polymerization reaction is possible at a low temperature underan atmospheric pressure, and the molecular weight is easily controlled.The above interfacial polymerization is preferably conducted in thepresence of an acid binder and an organic solvent. Furthermore, theabove interfacial polymerization may comprise, for example, the steps ofconducting pre-polymerization, then adding a coupling agent and againconducting polymerization. In this case, the copolycarbonate having ahigh molecular weight can be obtained.

The materials used in the interfacial polymerization are notparticularly limited as long as they can be used in the polymerizationof polycarbonates. The used amount thereof may be controlled asrequired.

The acid binding agent may include, for example, alkali metal hydroxidessuch as sodium hydroxide or potassium hydroxide, or amine compounds suchas pyridine.

The organic solvent is not particularly limited as long as it is asolvent that can be usually used in the polymerization of polycarbonate.As one example, halogenated hydrocarbon such as methylene chloride orchlorobenzene can be used.

Further, during the interfacial polymerization, a reaction accelerator,for example, a tertiary amine compound such as triethylamine,tetra-n-butyl ammonium bromide and tetra-n-butylphosphonium bromide or aquaternary ammonium compound or a quaternary phosphonium compound may befurther used for accelerating the reaction.

In the interfacial polymerization, the reaction temperature ispreferably from 0 to 40° C. and the reaction time is preferably from 10minutes to 5 hours. Further, during the interfacial polymerizationreaction, pH is preferably maintained at 9 or more, or 11 or more.

In addition, the interfacial polymerization may be conducted by furtherincluding a molecular weight modifier. The molecular weight modifier maybe added before the initiation of polymerization, during the initiationof polymerization, or after the initiation of polymerization.

As the above molecular weight modifier, mono-alkylphenol may be used. Asone example, the mono-alkylphenol is one or more selected from the groupconsisting of p-tert-butylphenol, p-cumyl phenol, decyl phenol, dodecylphenol, tetradecyl phenol, hexadecyl phenol, octadecyl phenol, eicosylphenol, docosyl phenol and triacontyl phenol, and preferablyp-tert-butylphenol. In this case, the effect of adjusting the molecularweight control is great.

The above molecular weight modifier is contained, for example, in anamount of not less than 0.01 parts by weight, not less than 0.1 parts byweight, or not less than 1 part by weight; and not more than 10 parts byweight, not more than 6 parts by weight, or not more than 5 parts byweight, based on 100 parts by weight of the aromatic diol compound.Within this range, the required molecular weight can be obtained.

In addition, the present invention provides a polycarbonate compositioncomprising the above-mentioned copolycarbonate and polycarbonate.

The copolycarbonate may be used alone, but it can be used together withthe polycarbonate as needed to thereby control the physical propertiesof the copolycarbonate.

The above polycarbonate is distinguished from the copolycarbonateaccording to the present invention in that a polysiloxane structure isnot introduced in a main chain of the polycarbonate.

Preferably, the above polycarbonate comprises a repeating unitrepresented by the following Chemical Formula 4:

in the above Chemical Formula 4,

R′₁, R′₂, R′₃ and R′₄ are each independently hydrogen, C₁₋₁₀ alkyl,C₁₋₁₀ alkoxy, or halogen,

Z′ is C₁₋₁₀ alkylene unsubstituted or substituted with phenyl, C₃₋₁₅cycloalkylene unsubstituted or substituted with C₁₋₁₀ alkyl, O, S, SO,SO₂ or CO.

Further, preferably, the above polycarbonate has a weight averagemolecular weight of 15,000 to 35,000 g/mol. More preferably, the aboveweight average molecular weight (g/mol) is not less than 20,000, notless than 21,000, not less than 22,000, not less than 23,000, not lessthan 24,000, not less than 25,000, not less than 26,000, not less than27,000, or not less than 28,000. Further, the above weight averagemolecular weight (g/mol) is not more than 34,000, not more than 33,000,or not more than 32,000.

The repeating unit represented by Chemical Formula 4 is formed byreacting the aromatic diol compound and the carbonate precursor. Thearomatic diol compound and the carbonate precursor that can be usedherein are the same as previously described for the repeating unitrepresented by Chemical Formula 1.

Preferably, R′₁, R′₂, R′₃, R′₄ and Z′ in Chemical Formula 4 are the sameas previously described for R₁, R₂, R₃, R₄ and Z in Chemical Formula 1,respectively.

Further, preferably, the repeating unit represented by Chemical Formula4 is represented by the following Chemical Formula 4-1:

In the polycarbonate composition, the weight ratio of thecopolycarbonate and the polycarbonate is preferably from 99:1 to 1:99,more preferably from 90:10 to 50:50, and most preferably from 80:20 to60:40.

In addition, the present invention provides an article comprising theabove-mentioned copolycarbonate or the copolycarbonate composition.

Preferably, the above article is an injection molded article. Inaddition, the article may further comprise, for example, one or moreselected from the group consisting of antioxidants, heat stabilizers,light stabilizers, plasticizers, antistatic agents, nucleating agents,flame retardants, lubricants, impact reinforcing agents, fluorescentbrightening agents, ultraviolet absorbers, pigments and dyes.

The method for preparing the article may comprise the steps of mixingthe copolycarbonate according to the present invention and additivessuch as antioxidants using a mixer, extrusion-molding the mixture withan extruder to produce a pellet, drying the pellet and then injectingthe dried pellet with an injection molding machine.

ADVANTAGEOUS EFFECTS

As set forth above, according to the present invention, thecopolycarbonate in which a specific siloxane compound is introduced in amain chain of the polycarbonate has small difference between an impactstrength at room temperature and an impact strength at low-temperatureand thus exhibits an excellent impact resistance.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Below, preferred embodiments will be provided in order to assist in theunderstanding of the present disclosure. However, these examples areprovided only for illustration of the present invention, and should notbe construed as limiting the present invention by the examples.

Preparation Example 1 Preparation of AP-PDMS (n=34)

47.60 g (160 mmol) of octamethylcyclotetrasiloxane and 2.40 g (17.8mmol) of tetramethyldisiloxane were mixed. The mixture was then placedin 3 L flask together with 1 part by weight of an acid clay (DC-A3)compared to 100 parts by weight of octamethylcyclotetrasiloxane, andreacted at 60° C. for 4 hours. After completion of the reaction, thereaction product was diluted with ethyl acetate and quickly filteredusing a celite. The repeating unit (n) of the terminal-unmodifiedpolyorganosiloxane thus prepared was 34 when confirmed through ¹H NMR.

To the resulting terminal-unmodified polyorganosiloxane, 4.81 g (35.9mmol) of 2-allylphenol and 0.01 g (50 ppm) of Karstedt's platinumcatalyst were added and reacted at 90° C. for 3 hours. After completionof the reaction, the unreacted siloxane was removed by conductingevaporation under the conditions of 120° C. and 1 torr. Theterminal-modified polyorganosiloxane thus prepared was designated asAP-PDMS (n=34). AP-PDMS was a pale yellow oil and the repeating unit (n)was 34 when confirmed through ¹H NMR using a Varian 500 MHz, and furtherpurification was not required.

Preparation Example 2 Preparation of MBHB-PDMS (m=58)

47.60 g (160 mmol) of octamethylcyclotetrasiloxane and 1.5 g (11 mmol)of tetramethyldisiloxane were mixed. The mixture was then introduced in3 L flask together with 1 part by weight of an acid clay (DC-A3)compared to 100 parts by weight of octamethylcyclotetrasiloxane, andreacted at 60° C. for 4 hours. After completion of the reaction, thereaction product was diluted with ethyl acetate and quickly filteredusing a celite. The repeating unit (m) of the terminal-unmodifiedpolyorganosiloxane thus prepared was 58 when confirmed through ¹H NMR.

To the resulting terminal-unmodified polyorganosiloxane, 6.13 g (29.7mmol) of 3-methylbut-3-enyl 4-hydroxybenzoate and 0.01 g (50 ppm) ofKarstedt's platinum catalyst were added and reacted at 90° C. for 3hours. After completion of the reaction, the unreacted siloxane wasremoved by conducting evaporation under the conditions of 120° C. and 1torr. The terminal-modified polyorganosiloxane thus prepared wasdesignated as MBHB-PDMS (m=58). MBHB-PDMS was a pale yellow oil and therepeating unit (m) was 58 when confirmed through ¹H NMR using a Varian500 MHz, and further purification was not required.

Preparation Example 3 Eugenol-PDMS

47.60 g (160 mmol) of octamethylcyclotetrasiloxane and 1.7 g (13 mmol)of tetramethyldisiloxane were mixed. The mixture was then placed in 3 Lflask together with 1 part by weight of an acid clay (DC-A3) compared to100 parts by weight of octamethylcyclotetrasiloxane, and reacted at 60°C. for 4 hours. After completion of the reaction, the reaction productwas diluted with ethyl acetate and quickly filtered using a celite. Therepeating unit (n) of the terminal-unmodified polyorganosiloxane thusprepared was 50 when confirmed through ¹H NMR.

To the resulting terminal-unmodified polyorganosiloxane, 6.13 g (29.7mmol) of Eugenol and 0.01 g (50 ppm) of Karstedt's platinum catalystwere added and reacted at 90° C. for 3 hours. After completion of thereaction, the unreacted siloxane was removed by conducting evaporationunder the conditions of 120° C. and 1 torr. The terminal-modifiedpolyorganosiloxane thus prepared was designated as Eugenol-PDMS.Eugenol-PDMS was a pale yellow oil and the repeating unit (n) was 50when confirmed through ¹H NMR using a Varian 500 MHz, and furtherpurification was not required.

Example 1

1784 g of water, 385 g of NaOH and 232 g of BPA (bisphenol A) were addedto a polymerization reactor, and dissolved with mixing under a N₂atmosphere. 4.3 g of PTBP (para-tert butylphenol) and the mixed solution(weight ratio of 90:10) of 5.91 g of AP-PDMS (n=34) prepared inPreparation Example 1 and 0.66 g of MBHB-PDMS (m=58) prepared inPreparation Example 2 were dissolved in MC (methylene chloride) andadded thereto. Subsequently, 128 g of TPG (triphosgene) was dissolved inMC and a dissolved TPG solution added thereto and reacted for 1 hourwhile maintaining pH of the TPG solution at 11 or more. After 10minutes, 46 g of TEA (triethylamine) was added thereto to conduct acoupling reaction. After a total reaction time of 1 hour and 20 minutes,pH was lowered to 4 to remove TEA, and pH of a produced polymer wasadjusted to neutral pH of 6 to 7 by washing three times with distilledwater. The polymer thus obtained was re-precipitated in a mixed solutionof methanol and hexane, and then dried at 120° C. to give a finalcopolycarbonate.

Example 2

The copolycarbonate was prepared in the same method as in Example 1,except that the weight ratio of AP-PDMS (n=34) and MBHB-PDMS (m=58) was95:5.

Example 3

The copolycarbonate was prepared in the same method as in Example 1,except that the weight ratio of AP-PDMS (n=34) and MBHB-PDMS (m=58) was97:3.

Example 4

The copolycarbonate was prepared in the same method as in Example 1,except that the weight ratio of AP-PDMS (n=34) and MBHB-PDMS (m=58) was99:1.

Example 5

The copolycarbonate was prepared in the same method as in Example 1,except that the weight ratio of AP-PDMS (n=34) and MBHB-PDMS (m=58) was95:5 and the addition amount of the molecular weight modifier PTBP(para-tort butylphenol) was adjusted.

Comparative Example 1

1784 g of water, 385 g of NaOH and 232 g of BPA (bisphenol A) were addedto a polymerization reacotor, and dissolved with mixing under a N₂atmosphere. 4.3 g of PTBP (para-tert butylphenol) and 6.57 g ofEugenol-PDMS prepared in Preparation Example 3 were dissolved in MC(methylene chloride) and added thereto. Subsequently, 128 g of TPG(triphosgene) was dissolved in MC and a dissolved TPG solution addedthereto and reacted for 1 hour while maintaining pH of the TPG solutionat 11 or more. After 10 minutes, 46 g of TEA (triethylamine) was addedthereto to conduct a coupling reaction. After a total reaction time of 1hour and 20 minutes, pH was lowered to 4 to remove TEA, and pH of aproduced polymer was adjusted to neutral pH of 6 to 7 by washing threetimes with distilled water. The polymer thus obtained wasre-precipitated in a mixed solution of methanol and hexane, and thendried at 120° C. to give a final copolycarbonate.

Comparative Example 2

The copolycarbonate was prepared by the same method as in ComparativeExample 1, except that AP-PDMS was used instead of Eugenol-PDMS.

Experimental Example Confirmation of Characteristics of Copolycarbonate

The weight average molecular weight of the copolycarbonate prepared inthe Examples and Comparative Examples were measured by GPC using PCStandard with Agilent 1200 series.

In addition, with respect to 1 part by weight of the respectivecopolycarbonate prepared in the Examples and Comparative Examples, 0.050parts by weight of tris(2,4-di-tert-butylphenyl)phosphite, 0.010 partsby weight of octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate,and 0.030 parts by weight of pentaerythritol tetrastearate were addedthereto, and the resulting mixture was pelletized using a φ30 mmtwin-screw extruder provided with a vent, and was injection-molded at acylinder temperature of 300° C. and a mold temperature of 80° C. usingthe N-20C injection molding machine of JSW Co., Ltd to prepare a desiredspecimen.

The characteristics of the above specimens were measured in thefollowing manner and the results were shown in Table 1 below.

1) Impact strength at room temperature: measured at 23° C. in accordancewith ASTM D256 (⅛ inch, Notched Izod).

2) Impact strength at low-temperature: measured at −30° C. in accordancewith ASTM D256 (⅛ inch, Notched Izod).

3) YI (yellow index): Specimen (width/length/thickness=60 mm/40 mm/3 mm)was injection-molded at 300° C., and then YI (yellow index) was measuredunder the following conditions by using Color-Eye 7000A (X-rite Inc.) inaccordance with ASTM 01925.

-   -   Measurement temperature: room temperature (23° C.)    -   Aperture size: Large area of view    -   Measurement method: transmittance was measured in a spiral range        (360 nm to 750 nm)

TABLE 1 Ex. 1 Ex. 2 Ex. 3 Ex. 4 Ex. 5 Com. Ex. 1 Com. Ex. 2 Weightaverage molecular 31,000 31,000 31,000 31,000 28,100 26,100 25,000weight (g/mol) Impact strength at room 963 940 880 850 845 802 650temperature(J/m) Impact strength at low- 902 840 750 700 678 678 533temperature (J/m) Impact strength at room 1.06 1.12 1.17 1.21 1.25 1.181.22 temperature/Impact strength at low-temperature YI (Yellow Index)6.27 5.55 5.21 4.21 2.43 6.74 3.71

As shown in Table 1 above, the copolycarbonate according to the presentinvention had superior impact strength at low-temperature and impactstrength at room temperature as compared with Comparative Examples 1 and2. In particular, the copolycarbonate according to the present inventionhad small difference between an impact strength at room temperature andan impact strength at low-temperature and thereby exhibited excellentimpact resistance.

The invention claimed is:
 1. A polycarbonate composition comprising: apolycarbonate; and a copolycarbonate, wherein the copolycarbonatecomprises: an aromatic polycarbonate-based first repeating unit; andaromatic polycarbonate-based second repeating units having siloxanebonds, wherein the ratio of an impact strength at room temperature andan impact strength at low-temperature (impact strength at roomtemperature/impact strength at low-temperature) as measured at 23° C.and −30° C., respectively, in accordance with ASTM D256 (⅛ inch, NotchedIzod) is 1.01 to 1.30, and the impact strength at room temperature is840 to 1000 J/m, and wherein the second repeating units comprise arepeating unit represented by Chemical Formula 2 and a repeating unitrepresented by Chemical Formula 3:

in Chemical Formula 2, each of X₁ is independently C₁₋₁₀ alkylene, eachof R₅ is independently hydrogen; C₁₋₁₅ alkyl unsubstituted orsubstituted with oxiranyl, oxiranyl-substituted C₁₋₁₀ alkoxy, or C₆₋₂₀aryl; halogen; C₁₋₁₀ alkoxy; allyl; C₁₋₁₀ haloalkyl; or C₆₋₂₀ aryl, andn is an integer of 10 to 200,

in Chemical Formula 3, each of X₂ is independently C₁₋₁₀ alkylene, eachof Y₁ is independently hydrogen, C₁₋₆ alkyl, halogen, hydroxy, C₁₋₆alkoxy, or C₆₋₂₀ aryl, each of R₆ is independently hydrogen; or C₁₋₁₅alkyl unsubstituted or substituted with oxiranyl, oxiranyl-substitutedC₁₋₁₀ alkoxy, or C₆₋₂₀ aryl; halogen; C₁₋₁₀ alkoxy; allyl; C₁₋₁₀haloalkyl; or C₆₋₂₀ aryl, and m is an integer of 10 to
 200. 2. Thepolycarbonate composition of claim 1, wherein the impact strength atlow-temperature is 650 to 950 J/m.
 3. The polycarbonate composition ofclaim 1, wherein the melt index as measured in accordance with ASTMD1238 (300° C., 1.2 kg conditions) is 3 to 20 g/10 min.
 4. Thepolycarbonate composition of claim 1, wherein the copolycarbonate has aweight average molecular weight of 1,000 to 100,000 g/mol.
 5. Thepolycarbonate composition of claim 1, wherein the first repeating unitis represented by Chemical Formula 1:

in Chemical Formula 1, R₁, R₂, R₃ and R₄ are each independentlyhydrogen, C₁₋₁₀ alkyl, C₁₋₁₀ alkoxy, or halogen, and Z is C₁₋₁₀ alkyleneunsubstituted or substituted with phenyl, C₃₋₁₅ cycloalkyleneunsubstituted or substituted with C₁₋₁₀ alkyl, O, S, SO, SO₂, or CO. 6.The polycarbonate composition of claim 5, wherein the repeating unitrepresented by Chemical Formula 1 is derived from one or more aromaticdiol compounds selected from the group consisting ofbis(4-hydroxyphenyl)methane, bis(4-hydroxyphenyl)ether,bis(4-hydroxyphenyl)sulfone, bis(4-hydroxyphenyl)sulfoxide,bis(4-hydroxyphenyl)sulfide, bis(4-hydroxyphenyl)ketone,1,1-bis(4-hydroxyphenyl)ethane, bisphenol A,2,2-bis(4-hydroxyphenyl)butane, 1,1-bis(4-hydroxyphenyl)cyclohexane,2,2-bis(4-hydroxy-3,5-dibromophenyl)propane,2,2-bis(4-hydroxy-3,5-dichlorophenyl)propane,2,2-bis(4-hydroxy-3-bromophenyl)propane,2,2-bis(4-hydroxy-3-chlorophenyl)propane,2,2-bis(4-hydroxy-3-methylphenyl)propane,2,2-bis(4-hydroxy-3,5-dimethylphenyl)propane,1,1-bis(4-hydroxyphenyl)-1-phenyl ethane,bis(4-hydroxyphenyl)diphenylmethane, andα,ω-bis[3-(o-hydroxyphenyl)propyl]polydimethylsiloxane.
 7. Thepolycarbonate composition of claim 5, wherein the Chemical Formula 1 isrepresented by the following Chemical Formula 1-1:


8. The polycarbonate composition of claim 1, wherein the weight ratio ofthe repeating unit represented by Chemical Formula 2 and the repeatingunit represented by Chemical Formula 3 is 99:1 to 1:99.
 9. Thepolycarbonate composition of claim 1, wherein the repeating unitrepresented by Chemical Formula 2 is represented by the followingChemical Formula 2-2:


10. The polycarbonate composition of claim 1, wherein the repeating unitrepresented by Chemical Formula 3 is represented by the followingChemical Formula 3-2:


11. The polycarbonate composition of claim 1, wherein a polysiloxanestructure is not introduced in a main chain of the polycarbonate. 12.The polycarbonate composition of claim 1, wherein the polycarbonatecomprises a repeating unit represented by Chemical Formula 4:

in the above Chemical Formula 4, R′₁, R′₂, R′₃ and R′₄ are eachindependently hydrogen, C₁₋₁₀ alkyl, C₁₋₁₀ alkoxy or halogen, and Z′ isC₁₋₁₀ alkylene unsubstituted or substituted with phenyl, C₃₋₁₅cycloalkylene unsubstituted or substituted with C₁₋₁₀ alkyl, O, S, SO,SO₂ or CO.